Testing Decisions
1. framework
2. Assertion Library
3. Helper Libraries
4. Where to run tests
5. Where to place tests
6. When to run tests

Reasons to use JEST as the testing framework
- fast
- only run tests related to changed code
- interactive watch mode
- snapshot testing
- helpful error messages
- debug via console or breakpoints
- mocks and spies
- coverage reporting
- simple configuration

  Types of